Aligner having shared rotation shaft

ABSTRACT

An illumination optical system is revolved at a given speed around a rotation shaft and emanates exposure light onto a reticle. The light having passed through the reticle is projected onto a semiconductor substrate, by means of a projection optical system which is revolved around the rotation shaft such that a relative positional relationship between the illumination optical system and the projection optical system is maintained.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a semiconductor manufacturingsystem, and more particularly, to an aligner for transferring a minutepattern, such as a semiconductor integrated circuit pattern.

[0003] 2. Description of the Background Art

[0004] A scan stepper has hitherto been employed as an aligner at thetime of forming a minute pattern such as a semiconductor integratedcircuit, during semiconductor manufacturing processes.

[0005] A conventional aligner will be now described.

[0006]FIG. 5 is a conceptual view for describing a conventional aligner,and FIG. 6 is a conceptual view for describing exposing operationperformed with the conventional aligner.

[0007] As shown in FIG. 5, reference numeral 101 designates anillumination optical system; 102 designates a reticle serving as anoriginal transfer plate; 103 designates a projection optical system; and104 designates a semiconductor substrate serving as a substrate on whicha pattern is to be transferred.

[0008] In the aligner shown in FIG. 5, the illumination optical system101 and the projection optical system 103 are fixed. While exposingoperation is performed, the reticle 102 and the semiconductor substrate104 are moved in synchronism with each other.

[0009] In more detail, as shown in FIG. 6, the reticle 102 and thesemiconductor substrate 104 are moved over a slit-shaped exposing region110, whereby a pattern 120 of the reticle 102 corresponding to theexposing region 110 is transferred onto the semiconductor substrate 104.

[0010] By means of moving the reticle 102 and the semiconductorsubstrate 104, the pattern 120 of the reticle 102, which extends beyondthe exposing region 110, is transferred onto the semiconductor substrate104.

[0011] However, in the above conventional aligner, a pattern 120 isexposed onto the semiconductor substrate 4 by means of moving thereticle 102 and the semiconductor substrate 104 in a synchronous mannerin one direction. During a period between a single exposing operationfor single shot (i.e., a single scanning operation) and the nextexposing operation, the reticle 102 and the semiconductor substrate 104are moved in the reverse direction.

[0012] For this reason, the conventional aligner must accelerate anddecelerate the reticle 102 and the semiconductor substrate 104 for everyscanning operation. Therefore, great stress is generated in the aligner.

[0013] The accuracy of pattern transfer is deteriorated by distortion orvibration ascribable to the stress.

SUMMARY OF THE INVENTION

[0014] The present invention has been conceived to solve thepreviously-mentioned problems and a general object of the presentinvention is to provide a novel and useful aligner for forming asemiconductor substrate by means of exposing, and is to provide a noveland useful method of manufacturing a semiconductor device using analigner.

[0015] A more specific object of the present invention is to provide analigner that forms a pattern on a semiconductor substrate with highaccuracy.

[0016] A more specific another object of the present invention is toform a pattern on a semiconductor substrate with high accuracy by use ofan aligner.

[0017] The above objects of the present invention are attained by afollowing aligner for forming a pattern on a semiconductor substrate bymeans of exposing, and by a following method of manufacturing asemiconductor device using an aligner.

[0018] According to one aspect of the present invention, aligner forforming a pattern on a semiconductor substrate by means of exposingcomprises a rotation shaft; an illumination optical system which isrevolved around the rotation shaft and emanates exposure light; areticle through which the exposure light originating from theillumination optical system is passed; and a projection optical systemwhich is revolved around the rotation shaft such that a relativepositional relationship between the illumination optical system and theprojection optical system is maintained, and the projection opticalsystem projects the light passed through the reticle onto thesemiconductor substrate.

[0019] In the aligner for forming a pattern on a semiconductor substrateby means of exposing, while exposing operation is performed, theillumination optical system and the projection optical system arerevolved around the rotation shaft.

[0020] Therefore, there is obviated a necessity of moving the reticleback and forth for a single shot of exposing, which would otherwise berequired by the conventional aligner. Thus, generation of stress can beprevented in the aligner, thereby enabling highly-accurate exposing of apattern.

[0021] According to another aspect of the present invention, in amanufacturing method of a semiconductor device using aligner, exposurelight is emanated onto a reticle from an illumination optical system,and the illumination optical system revolving around a rotation shaft inan emanation step. Next, the light passed through the reticle isprojected onto a semiconductor substrate by way of a projection opticalsystem, and the projection optical system revolving around the rotationshaft such that a relative positional relationship between theillumination optical system and the projection optical system ismaintained in a projection step.

[0022] In the method of manufacturing a semiconductor device, generationof stress can be prevented in the aligner, thereby enablinghighly-accurate exposing of a pattern, as well as the above-mentionedaligner.

[0023] Other objects and further features of the present invention willbe apparent from the following detailed description when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 is a conceptual view for describing an aligner, accordingto a first embodiment of the present invention;

[0025]FIG. 2 is a view for describing the movement of the exposingregion on the reticle during an exposing operation using the aligneraccording to the first embodiment;

[0026]FIG. 3 is a view for describing exposing of a pattern on asemiconductor substrate during an exposing operation using the aligneraccording to the first embodiment;

[0027]FIG. 4 is a view for describing a semiconductor substrate afterfinished exposing operation performed by the aligner according to thefirst embodiment;

[0028]FIG. 5 is a conceptual view for describing a conventional aligner;and

[0029]FIG. 6 is a conceptual view for describing exposing operationperformed with the conventional aligner.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] In the following, principles and embodiments of the presentinvention will be described with reference to the accompanying drawings.The members and steps that are common to some of the drawings are giventhe same reference numerals and redundant descriptions therefore may beomitted.

[0031] First Embodiment

[0032]FIG. 1 is a conceptual view for describing an aligner, accordingto a first embodiment of the present invention.

[0033] As shown in FIG. 1, reference numeral 1 designates anillumination optical system; 2 designates a reticle; 21 designates areticle holder; 3 designates a projection optical system; 31 designatesa first reflection mirror; 32 designates a second reflection mirror; and33 designates a projection lens. Moreover, reference numeral 4designates a semiconductor substrate; 41 designates a stage; 5designates a support/rotation mechanism; 51 designates a rotation shaft;52 designates a rotary plate; and 53 designates a support plate.

[0034] The illumination optical system 1 emanates exposure light ontothe reticle 2. The illumination optical system 1 is disposed on therotary plate 52, and the system 1 is revolved around the rotation shaft51 in conjunction with rotation of the rotary plate 52.

[0035] The reticle 2 is an original transfer plate having a patterndrawn thereon. The exposure light emanated from the illumination opticalsystem 1 is passed through the reticle 2. The reticle 2 is held by thereticle holder 21. The reticle 2 and the reticle holder 21 are placed onthe support plate 53, which does not rotate.

[0036] The projection optical system 3 is disposed on a rotary plate(not shown) of the support/rotation mechanism 5, and the system 3 isrevolved around the rotation shaft 51 such that the relative positionalrelationship (to be described later) between the projection opticalsystem 3 and the illumination optical system 1 is maintained. Theprojection optical system 3 projects the light passed through thereticle 2 onto the semiconductor substrate 4. More specifically, theprojection optical system 3 transfers an inverted-and-reversed image ofthe pattern of the reticle 2 onto the semiconductor substrate 4.

[0037] The projection optical system 3 comprises a first reflectionmirror 31, a second reflection mirror 32 and a projection lens 33. Thetwo reflection mirrors 31 and 32 and the projection lens 33 are disposedon the rotary plate (not shown), and are revolved around the rotationshaft 51 so as to maintain a positional relationship to be describedlater; i.e., a relative positional relationship among the reflectionmirrors 31 and 32, the projection lens 33 and the illumination opticalsystem 1.

[0038] The first reflection mirror 31 is disposed such that a reflectionsurface 31 a is spaced distance R2 away from the axis of the rotationshaft 51. The second reflection mirror 32 is disposed such that areflection surface 32 a is spaced distance R1 away from the axis of therotation shaft 51. The projection lens 33 is interposed between thesecond reflection mirror 32 and the semiconductor substrate 4.

[0039] Here, “R1” is the distance from the reflection surface 32 a tothe axis of the rotation shaft 51 (i.e., a distance from an optical axisB to be projected on the semiconductor substrate 4 to the axis of therotation shaft 51), and “R2” is the distance from the reflection surface31 a to the axis of the rotation shaft 51 (i.e., a distance from anoptical axis A passing through the reticle 2 to the axis of the rotationshaft 51). Further, a ratio of R2 to R1 (R2/R1) accurately matches ascale-down factor.

[0040] Hence, geometrical similarity equal to the scale-down factor(R2/R1) exists between the movement of an exposing region 20 on thereticle 2 relative to the rotation shaft 51 and the movement of anexposing region on the semiconductor substrate 4 relative to therotation shaft 51.

[0041] The first reflection mirror 31 reflects the light passed throughthe reticle 2 in a horizontal direction. The second reflection mirror 32reflects the light reflected from the first reflection mirror 31 in thedirection perpendicular to the surface of the semiconductor substrate 4;that is, toward the projection lens 33. The projection lens 33 projectsthe light reflected from the second reflection mirror 32 onto thesemiconductor substrate 4 in a scaled-down manner.

[0042] The semiconductor substrate 4 is a wafer coated with, forexample, a photosensitive agent (photoresist). The semiconductorsubstrate 4 is held by the stage 41, which does not rotate. After havingbeen exposed to a single shot of pattern, the semiconductor substrate 4is moved in a stepwise manner by means of the stage 41 (Steppingmovement shown in FIG. 3).

[0043] The support/rotation mechanism 5 comprises the rotation shaft 51,the rotary plate 52 and the support plate 53. Further, thesupport/rotation mechanism 5 comprises a rotary plate (not shown) whichrotates around the rotation shaft 51. The projection optical system 3 isdisposed on the rotary plate.

[0044] The illumination optical system 1 is disposed on the primarysurface of the rotary plate 52, and the rotary plate 52 rotates aroundthe rotation shaft 51.

[0045] The support plate 53 is for holding the reticle holder 21, andthe support plate 53 is fixed, i.e. not rotate.

[0046] The illumination optical system 1 and the projection opticalsystem 3 are revolved at a given speed by means of the respective rotaryplates of the support/rotation mechanism 5. Preferably, the speed is setwithin the range of 0.5 to 3.0 m/sec.. The reason for this is that, ifthe speed assumes a value of under 0.5 m/sec., throughput becomesinsufficient. In contrast, if the speed exceeds 3.0 ml/sec., fixation ofthe projection lens 33 becomes difficult.

[0047] The above-described aligner can be summarized as follows: theillumination optical system 1 emanates exposure light while revolvingaround the rotation shaft 51. The reticle 2 pass through the exposurelight originating from the illumination optical system 1. The projectionoptical system 3 is revolved around the rotation shaft 51 such that therelative positional relationship between the illumination optical system1 and the projection optical system 3, and the projection optical system3 projects the light passed through the reticle 2 onto the semiconductorsubstrate 4.

[0048] Next, with reference to FIGS. 1 to 4, the exposing method usingthe aligner according to the present embodiment will now be described.

[0049]FIG. 2 is a view for describing the movement of the exposingregion on the reticle during an exposing operation using the aligneraccording to the present embodiment. FIG. 3 is a view for describingexposing of a pattern on a semiconductor substrate during an exposingoperation using the aligner according to the present embodiment. FIG. 4is a view for describing a semiconductor substrate after finishedexposing operation performed by the aligner according to the presentembodiment.

[0050] As shown in FIG. 1, the illumination optical system 1 is revolvedaround the rotation shaft 51, and the illumination optical system 1emanates exposure light onto the reticle 2. The projection opticalsystem 3 is revolved around the rotation shaft 51 as well as theillumination optical system 1. Here, the illumination optical system 1and the projection optical system 3 are revolved around the rotationshaft 51 in conjunction with each other such that the relativepositional relationship between the illumination optical system 1 andthe projection optical system 3 (described previously) is maintained.The illumination optical system 1 and the projection optical system 3are revolved at a given speed, wherein the speed is set within a rangeof 0.5 to 3.0 m/sec.

[0051] As shown in FIG. 2, when the illumination optical system 1 isrevolved in the manner as mentioned above, the wedge-shaped exposingregion (exposing slit) 11 is moved over the pattern 20 of the reticle 2.

[0052] Here, an integrated amount of exposure light (illumination light)at an arbitrary point on the pattern 20 of the reticle 2 over which theexposing region 11 has moved becomes uniform.

[0053] Next, the light passed through the reticle 2 is projected ontothe semiconductor substrate 4 by means of the projection optical system3.

[0054] More specifically, the light passed through the reticle 2 isreflected by the first reflection mirror 31 in a horizontal direction,wherein the reflection surface 31 a of the first reflection mirror 31 isspaced only distance R2 away from the axis of the rotation shaft 51.

[0055] Next, the light reflected from the first reflection mirror 31 isreflected by the second reflection mirror 32 in a perpendiculardirection; that is, toward the projection lens 33, wherein thereflection surface 32 a of the second reflection mirror 32 is spacedonly distance R1 away from the axis of the rotation shaft 51.

[0056] Next, the light reflected from the second reflection mirror 32 isprojected onto the semiconductor substrate 4 by way of the projectionlens 33.

[0057] As shown in FIG. 3, by means of the above-described exposingoperation, the image of the pattern 20 of the reticle 2, which isexposed through the exposing region 11, is formed on the semiconductorsubstrate 4 as an inverted-and-reduced image (40).

[0058] Here, as shown in FIG. 1, the illumination optical system 1 andthe projection optical system 3 are disposed such that the ratio ofdistance R2 from the optical axis A to the axis of the rotation shaft 51to distance R1 from the optical axis B to the axis of the rotation shaft51; that is, R2/R1, becomes identical with the scale-down factor bywhich the pattern 20 on the reticle 2 is to be pattern 40 onto thesemiconductor substrate 4 by means of exposing.

[0059] Accordingly, a reduced pattern 40 which is symmetrical about thepattern 20 on the reticle 2 and converges with respect to a point on therotation shaft 51 is patterned onto the semiconductor substrate 4 bymeans of a single shot of exposing.

[0060] After the semiconductor substrate 4 has been moved stepwise inthe manner (Stepping movement) as shown in FIG. 3, the above-mentionedexposing operations are repeated.

[0061] After all the exposing operations have been completed, aplurality of patterns 40 are formed over the entire surface of thesemiconductor substrate 4, as shown in FIG. 4.

[0062] As described above, in the aligner and the exposing methodaccording to the first embodiment, the illumination optical systems 1and the projection optical system 3 are revolved around the rotationshaft 51, and the pattern 20 drawn on the reticle 2 is patterned ontothe semiconductor substrate 4 through exposing.

[0063] There is obviated a necessity of moving the reticle 2 back andforth every exposing of a single shot, which would otherwise be requiredby the conventional aligner. Thus, generation of stress can be preventedin the aligner. Therefore, distortion and vibration of the aligner canbe prevented, thereby enabling highly-accurate exposing of a pattern.

[0064] The optical systems 1 and 3 are revolved at a given speed, henceexposing operation can be performed stably, thereby enablinghighly-accurate exposing of a pattern. Further, the speed is set to avalue ranging from 0.5 to 3.0 m/sec., thereby improving throughput.

[0065] The above-mentioned aligner has a pair of optical systems; thatis, one illumination optical system 1 and one projection optical system3. The aligner may be provided with a plurality of sets of opticalsystems. In this case, exposing operation can be performed a pluralityof times during a single rotation of the rotation table 52. Therefore,throughput can be improved to a much greater extent.

[0066] Further, a plurality of pairs of optical systems 1 and 3 aredisposed at uniform intervals around the rotation shaft 51, therebyimproving a balance in weight of the aligner. Accordingly, distortion orvibration of the aligner can be prevented, thereby enabling a furtherstable exposing operation. Further, as mentioned above, exposingoperation is performed at a given rotation speed, thereby enablingconsiderably-stable exposing operation. Hence, a pattern can be exposedat high speed and with high accuracy.

[0067] The balance in weight of the aligner can be improved, by means ofarranging weights which are equal in weight and center of gravity withthe optical systems 1 and 3, thereby enabling stable exposing of apattern.

[0068] The plurality of illumination optical systems 1 which emanateexposure light of respective different wavelengths, or the pluralityprojection optical system 3 having lenses of respective differentnumerical apertures (N.A.) may be used. Thus, exposure under a pluralityof exposing conditions can be performed in the aligner.

[0069] The aligner according to the present embodiment may be providedwith a plurality of reticles 2 and a plurality of semiconductorsubstrates 4 corresponding to the reticles 2. As a result, the pluralityof semiconductor substrates 4 can be exposed to the light during asingle rotation of the optical systems 1 and 3. Therefore, throughputcan be improved. In addition, if the aligner employs the above-mentionedplurality of sets of optical systems 1 and 3, the throughput can beimproved to much a greater extent.

[0070] This invention, when practiced illustratively in the mannerdescribed above, provides the following major effects:

[0071] According to a first aspect of the present invention, generationof stress in an aligner can be prevented, thereby enablinghighly-accurate exposing of a pattern.

[0072] In a preferred variation of the present invention, aninverted-and-reduced image of a reticle can be exposed onto asemiconductor substrate with high accuracy by means of exposing.

[0073] In a preferred variation of the present invention, anillumination optical system and a projection optical system are revolvedat a given speed, thereby enabling stable exposing of a pattern.

[0074] In a preferred variation of the present invention, since thespeed is set within the range of 0.5 to 3.0 m/sec., throughput can beimproved.

[0075] In a preferred variation of the present invention, a balance inweight of the aligner can be improved, and stable exposing of a patterncan be performed. Further, throughput can be improved.

[0076] In a preferred variation of the present invention, a pattern canbe exposed under different exposing conditions.

[0077] In a preferred variation of the present invention, a pattern canbe patterned onto a plurality of semiconductor substrates by means ofexposing, thereby improving throughput.

[0078] Further, the present invention is not limited to theseembodiments, but variations and modifications may be made withoutdeparting from the scope of the present invention.

[0079] The entire disclosure of Japanese Patent Application No.2000-379196 filed on Dec. 13, 2000 containing specification, claims,drawings and summary are incorporated herein by reference in itsentirety.

What is claimed is:
 1. An aligner for forming a pattern on a semiconductor substrate by means of exposing comprising: a rotation shaft; an illumination optical system which is revolved around said rotation shaft and emanates exposure light; a reticle through which said exposure light originating from said illumination optical system is passed; and a projection optical system which is revolved around said rotation shaft such that a relative positional relationship between said illumination optical system and said projection optical system is maintained, and said projection optical system projecting said light passed through said reticle onto said semiconductor substrate.
 2. The aligner for forming a pattern on a semiconductor substrate by means of exposing according to claim 1, wherein said projection optical system includes a first reflection mirror, a second reflection mirror and a projection lens, which are disposed such that a relative positional relationship to said illumination optical system is maintained; said first reflection mirror reflects said light passed through said reticle in a horizontal direction; said second reflection mirror reflects said light reflected from said first reflection mirror in a vertical direction; and said projection lens projects said light reflected from said second reflection mirror onto said semiconductor substrate in a scale-down manner.
 3. The aligner for forming a pattern on a semiconductor substrate by means of exposing according to claim 2, wherein the ratio of a distance from an axis of said rotation shaft to a reflection surface of said first reflection mirror to a distance from said axis of said rotation shaft to a reflection surface of said second reflection mirror is equal to a scale-down factor of said projection lens.
 4. The aligner for forming a pattern on a semiconductor substrate by means of exposing according to claim 1, wherein said illumination optical system and said projection optical system are revolved at a given speed.
 5. The aligner for forming a pattern on a semiconductor substrate by means of exposing according to claim 4, wherein said illumination optical system and said projection optical system are revolved at a speed of 0.5 to 3.0 m/sec.
 6. The aligner for forming a pattern on a semiconductor substrate by means of exposing according to claim 1, wherein a plurality of illumination optical systems are provided around said rotation shaft at uniform intervals, and a plurality of projection optical systems are provided so as to correspond to said respective illumination optical systems.
 7. The aligner for forming a pattern on a semiconductor substrate by means of exposing according to claim 6, wherein said plurality of illumination optical systems include illumination optical systems which emanate exposure light of different wavelengths.
 8. The aligner for forming a pattern on a semiconductor substrate by means of exposing according to claim 6, wherein said plurality of projection optical systems include projection optical systems having lenses of different numerical apertures.
 9. The aligner for forming a pattern on a semiconductor substrate by means of exposing according to claim 1, wherein a plurality of reticles are provided around said rotation shaft, and a plurality of semiconductor substrates are provided around said rotation shaft so as to correspond to said respective reticles.
 10. A method of manufacturing a semiconductor device using an aligner comprising: an emanation step of emanating exposure light onto a reticle from an illumination optical system, and said illumination optical system revolving around a rotation shaft; and a projection step of projecting light passed through said reticle onto a semiconductor substrate by way of a projection optical system, and said projection optical system revolving around said rotation shaft such that a relative positional relationship between said illumination optical system and said projection optical system is maintained.
 11. The method of manufacturing a semiconductor device using an aligner according to claim 10, wherein in said emanation step and said projection step, said illumination optical system and said projection optical system are revolved at a given speed.
 12. The method of manufacturing a semiconductor device using an aligner according to claim 11, wherein in said emanation step and said projection step, said illumination optical system and said projection optical system are revolved at a speed of 0.5 to 3.0 m/sec.
 13. The method of manufacturing a semiconductor device using an aligner according to claim 10, wherein a plurality of illumination optical systems are provided around said rotation shaft at uniform intervals, and a plurality of projection optical systems are provided so as to correspond to said respective illumination optical systems; said emanation step is performed by said plurality of illumination optical systems respectively; and said projection step is performed by said plurality of projection optical systems respectively.
 14. The method of manufacturing a semiconductor device using an aligner according to claim 13, wherein a plurality of reticles are provided around said rotation shaft, and a plurality of semiconductor substrates are provided so as to correspond to said respective reticles; said emanation step is performed by said plurality of illumination optical systems to said plurality of reticles respectively; and said projection step is performed by said plurality of projection optical systems to said plurality of semiconductor substrates respectively. 